Generally, a backlight unit of a liquid crystal display includes a reflective film, a diffusion film, a prism film, etc., in order to achieve high luminance and optical uniformity. Also, a luminance enhancement film is used, which may include a light diffusion film which randomly emits polarized light at a wider angle. As part of such a composite film, an attempt has been made to stack a film which may enhance luminance, for example, a reflective polarization film, and a film which may diffuse light, for example, a light diffusion film (Korean Unexamined Patent Application Publication No. 10-2006-055341).
Typically a light diffusion film is formed by coating a biaxially drawn polyethyleneterephthalate film useful as a base layer with a light diffusion layer. However, the light diffusion film having the above configuration may cause non-polarization or inverse scattering of polarized light, undesirably lowering the overall optical properties.